This invention relates to the generation of phototools and more specifically to the generation of masks and reticles used in the semiconductor industry.
Prior art in the semiconductor industry uses different methods to expose a layer of photoresist deposited on top of a metal layer in order to generate a phototool. After exposure the photoresist is developed and used as a mask for etching the metal layer (typically chrome deposited on quartz). Since a development process is involved, the pattern can not be inspected at the time of exposure. A second disadvantage of the development process is the potential increase in the number of defects caused by using a multi-step process. Prior attempts to generate processless phototools include ablation of a metal or polymer layer. These attempts were not completely successful since a very short wavelength, generated only be excimer lasers, is required for clean ablation. Excimer lasers have a low repetition rate, which has prevented their use in high data rate applications. Conventional light valves such as liquid crystals do not transmit well the short wavelength of the excimer lasers.